Marshalling yard retarder



y 1957 s. H. DANIELI I 3,332,519

MARSHALLING YARD RETARDER Filed June 15, 1966 IN VENT OR 75 #Q/AJ/K Dav 0 BY g 2 United States Patent 3,332,519 MARSHALLING YARD RETARDER Sten Henrik Danieli, Vasteras, Sweden, assignor to Allmiinna Svenska Elektriska Aktiebolaget, Vasteras, Sweden, a corporation of Sweden Filed June 15, 1966, Ser. No. 557,688 Claims priority, application Sweden, June 15, 1965, 7,847/65 8 Claims. (Cl. 188-62) The present invention relates to a retarder for marshalling yards comprising tracks for railway cars, especially a stationary retarder means having a'substantially cylindrical rotatable unit positioned substantially parallel to the track and provided with a helical contact surface arranged to set the rotatable unit in rotation under the influence of a passing railway car.

Hydraulic retarders of the above mentioned type are known. Such a retarder can be connected to a hydraulic or mechanical system which provides the actual retarding effect. The known systems, however, require considerable space, are explosive and complicated and have retarding properties which are relatively impractical for automatic marshalling yard systems.

The object of the present invention is to provide a simple and reliable retardcr of the type referred to, which is particularly suitable for automatic marshalling yard systems. The invention is characterized in that the rotatable unit is connected to a preferably built-in hydraulic retarding means arranged, preferably by throttling the flow of hydraulic medium, to give a retarding effect dependent upon the speed of rotation of the rotatable unit, said eifect being negligible at low speeds. According to -a preferred embodiment of the invention, the rotatable unit is designed with the contact surface forming one side of a radially projecting helical flange.

In the following the invention will be described more fully with reference to the accompanying figures which show schematically one embodiment of the invention. FIGURE 1 shows a side view of an arrangement according to the invention and FIG. 2 a section on the line A-A in FIG. 1. FIG. 3 shows in axial section a part of a retarder cylinder. FIG. 4 shows a double acting cylinder.

In the figures, 1 designates a wheel of a passing railway car. The track is composed of a rail 2 which in FIG- URE 1 has been simplified to a dotted line 2a which indicates the upper side of the rail. Parallel to the track and on the inside of the rails a rotatable cylinder is journalled. The cylinder 3 has a helical radially projecting flange 4 on which the flange 5 of the wheel 1 runs. When the wheel 1 passes the cylinder 3 this will be set in rotation by the forces transmitted from the wheel to the flange 4. This rotating movement is retarded and the retarding effect is then transmitted to the wheel 1 and consequently to the passing railway car.

The retarding eifect is produced with the help of a hydraulic medium. A hydraulic retarding unit with quite sufficient capacity can easily be built into the rotating cylinder 3, for example in the form of an axial piston pump. With suitable valves the hydraulic retarding system can in several different ways be arranged to give great retarding effect at high speed and very little retarding effect at low speed. This is most easily effected by providing for hydraulic medium to be pumped by the movement of the rotating cylinder 3 through a throttled through-flow opening. In this way quadratic characteristic of the retarding is obtained, that is, the retarding effect increases with the square of the speed. For such a system the retarding effect at low speeds is negligible. A low speed limit is obtained below which scarcely any retarding takes place. This limit can be varied by different dimensioning of the throttled through-flow openice ing. In order to obtain in a simple way a retarding system in which the running out speed of the railway cars can be varied, a number of retarding units having different low speed limits are arranged in sequence so that they form a series with successively decreasing speed limits. By setting one or more of the last retarding units in off position the passing railway cars are given the desired running out speed.

FIGURE 3 shows schematically one end of the cylinder 3 in section. The shaft 7 of the cylinder 3 carries an axial multi-piston pump 8 of conventional type. The shaft 7 is not rotatable and should be keyed to a bracket, for instance the link arm 6 (FIGS. 1 and 2). The rotation of the cylinder 3 in relation to the shaft 7 causes the pistons 9 of the pump to pump a hydraulic medium enclosed in the cylinder 3 through an inlet duct 10 to one of the pump cylinders 11, over to another pump cylinder 12 through internal ducts (not shown) and out through an outlet duct 13 and a pre-set or remote controlled throttle valve 14 determining the retarding characteristics of the unit.

The cylinder 3 may be provided with another pump of the same kind in its other end. In order to allow volume changes at different temperatures a suitable air-cushion means should be present in the cylinder.

The retarding means shown can only retard railway cars passing from right to left in FIGURE 1. So that the cylinder 3 can be passed by railway cars in the opposite direction, the cylinder 3 is carried by link arms 6 so that it is foldable and automatically moves to the side when a wheel passing from left to right meets the flange 4. The same thing happens if the cylinder is run over by any vehicle, for example an engine, so designed that the retarding arrangement cannot operate normally.

Normally retarding of running railway cars is only required in one direction. If a retarding means is desired which can be used in both directions, the cylinder 3 is made longer and provided with a left-hand helical flange 4 in one end and with a right-hand one in the other end. In this case, the flanges are arranged so that a wheel always first meets a flange facing the right way for retarding. The cylinder 3 is further provided with a spring or the like which after each retarding movement urges the cylinder to rotate in the opposite direction back to the starting position. The return movement caused by the spring means that the wheel can pass the helical flange facing the wrong way without the cylinder 3 having to be foldable.

A retarder cylinder constructed in this way is shown in FIGURE 4. The flange 4 is a left-hand helix in the left end and a right-hand helix in the right end of the cylinder. The retarding means (not shown in this figure) are of the kind shown in FIG. 3. Spring coils 15 wound in opposite directions are arranged to cause an immediate return movement when a wheel of a railway car from the left or from the right has passed along the first half of the cylinder.

The invention is not limited to the embodiment shown, but many variations and modifications are feasible within the scope of the following claims.

I claim:

1. Retarder arrangement for marshalling yards, comprising tracks for railway cars, a stationary retarder means having a substantially cylindrical rotatable unit positioned substantially parallel to one of said tracks and provided with a helical contact surface arranged to set said rotatable unit in rotation under the influence of a passing railway car, a hydraulic retarding system connected to said rotatable unit comprising means responsive to turning of said unit for exerting pressure on a hydraulic medium and means for throttling the flow of the hydraulic medium to give a retarding effect dependent upon the speed of rotation of the rotatable unit, said effect being negligible at low speeds.

2. Arrangement according to claim 1, said contact surface of the rotatable unit being one side of a radially projecting, helical flange.

3. Arrangement according to claim 1, comprising a plurality of said rotatable units arranged in sequence along the track with successively increasing retarding elfect at low speeds.

4. Arrangement according to claim 1, means mounting said rotatable unit foldingly beside said track.

5. Arrangement according to claim 4, said rotatable unit being mounted so that it automatically yields sideways when passed by a vehicle of a selected type.

6. Arrangement according to claim 1, said rotatable 15 unit being provided at one end with a right-hand helical contact surface and at the other end with a left-hand helical contact surface and with a return mechanism arranged to rotate the rotatable unit in opposite direction after a retarding operation.

7. Arrangement according to claim 1, said hydraulic retarding system being enclosed in said rotatable units. 8. Arrangement according to claim 7, said retarding system comprising an axial multi-piston pump.

References Cited UNITED STATES PATENTS 1,741,875 12/1929 Paul 18891 FOREIGN PATENTS 733,207 7/1955 Great Britain.

DUANE A-. REGER, Primary Examiner. 

1. RETARDER ARRANGMENT FOR MARSHALLING YARDS, COMPRISING TRACKS FOR RAILWAY CARS, A STATIONARY RETARDER MEANS HAVING A SUBSTANTIALLY CYLINDRICAL ROTATABLE UNIT POSITIONED SUBSTANTIALLY PARALLEL TO ONE OF SAID TRACKS AND PROVIDED WITH A HELICAL CONTACT SURFACE ARRANGED TO SET SAID ROTATABLE UNIT IN ROTATION UNDER THE INFLUENCE OF A PASSING RAILWAY CAR, A HYRAULIC RETARDING SYSTEM CONNECTED TO SAID ROTATABLE UNIT COMPRISING MEANS RESPONSIVE TO TURNING OF SAID UNIT FOR EXERTING PRESSURE ON A HYDRAULIC MEDIUM AND MEANS FOR THROTTLING THE FLOW OF THE HYDRAULIC MEDIUM TO GIVE A RETARDING EFFECT DEPENDENT UPON THE SPEED OF ROTATION OF THE ROTATABLE UNIT, SAID EFFECT BEING NEGLIGIBLE AT LOW SPEEDS. 